1. Field of the Invention
The invention relates to a sandwich component comprising a cellulose-based honeycomb core and at least one cover layer and to a method for the production thereof.
2. Description of Related Art including information Disclosed under 37 and 1.97 and 1.98
As part of the light-weight strategy, which in motor vehicle manufacture is in particular aimed at reducing both fuel costs and carbon dioxide emissions, components having a sandwich structure are increasingly used, having a significantly lower weight than conventional components owing to the low density of the core material while still being able to offer adequate strength values if a suitable cover layer material is selected. From the aerospace sector, sandwich components with a high load-bearing capacity are known, the honeycomb cores of which usually consists of high-value and therefore expensive phenolic resin-impregnated aramid paper. The cover layers are made of reinforcing fibers in a thermosetting matrix. Such sandwich components are primarily produced using the autoclave method or by hard laminating. These production methods allow only for short production runs and are highly cost-intensive and therefore not suitable for the mass production of motor vehicle components. In addition, the high-value materials contribute to high costs.
From prior art, DE 10 2007 007 554 A1 describes a rigid planar composite component of a vehicle which can be used as a sliding roof, a rear shelf, a loading platform or the like and a method for the production thereof. This composite component consists of a core layer placed between two cover layers—each made of a fiber-reinforced polyurethane layer—which core layer may have a honeycomb structure with a profiled reinforcing element embedded therein. To produce the composite component, the reinforcing element is first installed into recesses provided for this purpose in the core layer, the core layer is then placed between two fiber layers, each being sprayed with the polyurethane, and finally the sandwich is pressed in a pressing tool for shaping and curing the composite component.
WO 2004/080698 A1 further describes a method for the production of a thermoplastic composite structure reinforced with long fibers, using a hybrid or blended yarn of reinforcing and thermoplastic fibers which are fed to a heated and lobed nozzle in which the reinforcing fibers are intensively impregnated with the thermoplastic material. The thermoplastic fiber material comprises polyethylene, polyethylene terphthalate, polybutylene terphthalate, nylon, thermoplastic polyurethanes, polyacetal, polyphenyl sulphide, cyclo-olefin copolymers, thermotropic polyesters and blends thereof.